Gun



Patented Sept. 25, 1934 George M. McCann, New Castle, Del.

Application April 21, 1932, Serial No. 606,749

1 Claim.

(Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 0. G. 757) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

The subject of this invention is a gun.

The purpose of the present invention is to provide a gun that is designed in such a manner that it will permit the convenient insertion and removal of the inner tube, that may be readily and inexpensively manufactured and that will be reduced in weight for a given strength.

The gun is characterized by the employment of a combination breech ring and. jacket, by a novel method of holding the inner tube against longitudinal and rotational displacement and by a formation of the breech ring which will en- I able the tube to be inserted from the rear.

To these and other ends, the invention consists in the construction, arrangement and com- "bination of elements described hereinafter and pointed out in the claim forming a part of this specification.

A practical embodiment of the invention is illustrated in the accompanying drawing, where- Fig. 1 is a longitudinal horizontal sectional View through a gun constructed in accordance with the invention.

Fig. 2 is a sectional view on the line 2-2 of Fig. 1.

Fig. 3 is a view in rear elevation with the loading plate in place.

Figs. 4 and 5 are respectively views in rear and side elevation of the loading plate for the breech ring.

spectively 8a and 81), for loading and for permitting the insertion of the inner tube. The jacket is only of sufiicient length to provide for sliding engagement with the cradle of a gun mount. The outer tube 5 may or may not be 0. overstrained by working to give it a permanent set. The inner tube is preferably over-strained by working to give a permanent set before finished machining.

The inner tube has a free sliding fit in the outer tube. The diameters are so determined that the clearance between the tubes from the rear end to a point just forwardly of the front cone 9 of the cartridge or powder chamber establishes a radial play space that will be taken up during firing and restored after firing. The surface 66 plied by a relatively narrow collar 10 engageable with the forward end of the outer tube 5 and having the same clearance with respect to the outer tube as is provided for the main bearing. The collar 10 may be present as a separate packing member to exclude moisture.

The clearance 11 between the tubes from the forward end of the main bearing to the rear end of the auxiliary bearingis relatively great and is so determined that the opposite walls will not contact when the gun is in action. A considerable surface on both tubes may therefore be rough finished with a consequent reduction in the cost of manufacture.

The inner tube is formed externally with keys 12 receivable in key-ways 13 formed internally in the outer tube and disposed in a vertical plane so that the insertion of the inner tube will be facilitated. The keys are positioned on the rear end on the inner tube and have a length equal approximately to one-third the distance to the 35 rear forcing cone 14. They therefore occupy a position opposite the base of the cartridge case. The keys perform the usual function of holding the inner tube against rotational displacement.

The rear extremity of the inner tube includes 901 a collar 15 fitting in an annular recess 16 in the outer tube and cooperating therewith to hold the inner tube against forward displacement. The collar is formed with an aperture or recess 17 Fig. 1, for receiving a latch 18 having a tongue 5' and groove connection 19 with the outer tube 5 and secured thereto by means of a screw 20. The latch holds the inner tube against withdrawal. A clearance similar to that of the bearings is provided for the collar 15 and latch 18 as well as 1 0" for the keys 12.

Referring particularly to Figs. 4 and 5 a loading plate 21in the form of an open ring or band is placed in the horizontally disposed recess 8 of the outer tube and retained therein by means of spaced lugs 22 and 23 respectively formed on the plate 21 and the outer tube 5. The loading plate is further secured by means of a screw 24. As indicated in Fig. 3 the recess 8a is of sufficient diameter to provide for insertion and re- 11f) The interior of the outer tube and the exteriorof the inner tube may be tapered or cylindrical and any relation or combination of these shapes may exist.

I claim:

A gun comprising an outer tube including a breech ring having a recess with a round and a straight sided portion, an inner tube insertable in the outer tube by movement through the round portion of the recess, and a loading plate securable in the round portion of the recess of the breech ring and having inner sides in continuation of the straightsided portion of the recess in the outer tube.

GEORGE M. MCCANN. 

